Efeito da adubação silicatada em hortaliças não convencionais / Effect of silica fertilization on unconventional vegetables

Objetivou-se com esse trabalho verificar a capacidade de hortaliças não convencionais em acumular silício, bem como a resposta destas à adubação silicatada. O experimento foi conduzido em casa de vegetação em 2016. Foram avaliados duas doses de adubação silicatada (0 e 50 mg dm-3 de Si), e nove espécies de hortaliças não convencionais (Maranta arundinacea L., Rumex acetosa L., Amaranthus spinosus L., Amaranthus viridis L., Amaranthus retroflexus L., Amaranthus deflexus L., Amaranthus hybridus L., Stachys byzantina K. Koch e Sonchus oleraceus L.), dispostos em delineamento inteiramente casualizado em esquema fatorial 2 x 9, com quatro repetições. Foram determinadas a massas fresca e seca, assim como o teor de Si em todas as plantas. As espécies avaliadas possuem potencial para acumular silício mediante adubação com o elemento. A aplicação de 50 mg dm-3 de Si proporcionou maior teor de Si nas espécies estudadas. A adubação com Si, de modo geral, não influencia na biomassa dessas plantas.

The objective of this work was to verify the capacity of unconventional vegetables to accumulate silicon, as well as their response to silicate fertilization. The experiment was conducted in a greenhouse in 2016. Two doses of silicate fertilization (0 and 50 mg dm-3 of Si) and nine species of unconventional vegetables (Maranta arundinacea L., Rumex acetosa L., Amaranthus spinosus L., Amaranthus viridis L., Amaranthus retroflexus L., Amaranthus deflexus L., Amaranthus hybridus L., Stachys byzantina K. Koch and Sonchus oleraceus L.) were evaluated, arranged in a completely randomized design in a 2 x 9 factorial scheme, with four replicates. The fresh and dry masses and the Si content were determined in all the plants. The unconventional vegetable species evaluated have the potential to accumulate silicon through element fertilization. The application of 50 mg dm-3 of Si provided higher Si content in the studied species. Fertilization with Si does not generally influence plant biomass.

Efeito da adubação silicatada em hortaliças não convencionais / Effect of silica fertilization on unconventional vegetables

Objetivou-se com esse trabalho verificar a capacidade de hortaliças não convencionais em acumular silício, bem como a resposta destas à adubação silicatada. O experimento foi conduzido em casa de vegetação em 2016. Foram avaliados duas doses de adubação silicatada (0 e 50 mg dm-3 de Si), e nove espécies de hortaliças não convencionais (Maranta arundinacea L., Rumex acetosa L., Amaranthus spinosus L., Amaranthus viridis L., Amaranthus retroflexus L., Amaranthus deflexus L., Amaranthus hybridus L., Stachys byzantina K. Koch e Sonchus oleraceus L.), dispostos em delineamento inteiramente casualizado em esquema fatorial 2 x 9, com quatro repetições. Foram determinadas a massas fresca e seca, assim como o teor de Si em todas as plantas. As espécies avaliadas possuem potencial para acumular silício mediante adubação com o elemento. A aplicação de 50 mg dm-3 de Si proporcionou maior teor de Si nas espécies estudadas. A adubação com Si, de modo geral, não influencia na biomassa dessas plantas.(AU)

The objective of this work was to verify the capacity of unconventional vegetables to accumulate silicon, as well as their response to silicate fertilization. The experiment was conducted in a greenhouse in 2016. Two doses of silicate fertilization (0 and 50 mg dm-3 of Si) and nine species of unconventional vegetables (Maranta arundinacea L., Rumex acetosa L., Amaranthus spinosus L., Amaranthus viridis L., Amaranthus retroflexus L., Amaranthus deflexus L., Amaranthus hybridus L., Stachys byzantina K. Koch and Sonchus oleraceus L.) were evaluated, arranged in a completely randomized design in a 2 x 9 factorial scheme, with four replicates. The fresh and dry masses and the Si content were determined in all the plants. The unconventional vegetable species evaluated have the potential to accumulate silicon through element fertilization. The application of 50 mg dm-3 of Si provided higher Si content in the studied species. Fertilization with Si does not generally influence plant biomass.(AU)

Polyamines in conventional and organic vegetables exposed to exogenous ethylene.

Relationships between endogenous levels of polyamines by thin layer chromatography (TLC) and gas chromatography (GC), nitrate and response to the application of ethylene were established between organic and conventional vegetables (broccoli, collard greens, carrots and beets), both raw and cooked. Responses to ethylene showed that organic plants were less responsive to the growth regulator. The levels of free polyamines obtained by TLC were higher in organic vegetables. Organic broccoli showed higher levels of putrescine (Put), and cooking resulted in lowering the overall content of these amines. Conventional collard green showed the highest level of putrescine in the leaves compared with organic. Tubers of carrots and beets contain the highest levels of Put. These plants also contain high levels of spermine. GC analysis showed the highest polyamines contents compared with those obtained by TLC. Cooking process decreased putrescine and cadaverine content, both in conventionally and organically grown vegetables. Organic beets contain lower NO3(-) compared with its conventional counterpart.

Evaluation of vegetal extracts as biological herbi- and pesticides for their use in Cuban agriculture.

The idea of an interuniversity project between the Universidad Central de Las Villas, Cuba and the University of Ghent, Belgium was conceived in order to improve the quality of the Cuban agriculture and to stimulate its independence from foreign chemical farm inputs, starting with an applied ethnobotanical investigation as basis for the development of sustainable agricultural practices. The project consists of three parts. The first, ethnobotanical part, subtends the two subsequent stages, i.e. the phytochemical and pharmacological stages. After ethnobotanical inventarization of plants with a possible phytotoxic or pesticide effect, these will be collected and taxonomically defined. Fresh vegetal material will be dried and ground, and this first crude extract (polar or apolar) will be tested for its activity in in vitro biological tests. When results are positive (presence of activity), this crude extract will be tested in vivo, which could lead to immediate application in agriculture (short-term strategy). The long-term strategy will lead to the identification of chemical substances, responsible for the activity of the crude extract. As highly sophisticated apparatus is needed for this last step (i.e. identification of chemical compounds), this will be performed by the Department of Organic Chemistry, Faculty of Agricultural and Applied Biological Sciences of the University of Ghent. The project has started in September 2000. Apart from all the (complicated) administrative steps to be undertaken for its successful execution, the ethnobotanical and phytochemical parts have already started. Ethnobotanical data were gathered in view of recollection of "traditional botanical knowledge", considering three main approaches: the use of plants in medicine, in Cuban religion (the famous "santería") and the use of allelopathic plants in agriculture. Use of medicinal and religious plants is ubiquitous in Cuba. The concept of allelopathy, however, is much less known and applied. At this moment, and after preliminary screening and gathering of field data, in vitro germination tests are running, trying out extracts of tobacco (Nicotiana tabacum), banana (Musa spp.), sunflower (Helianthus annuus), Simarouba glauca and S. laevis (syn. Quassia, fam. Simaroubaceae).

Macrocyclic trichothecenes in Baccharis coridifolia plants and endophytes and Baccharis artemisioides plants.

Toxic disease in livestock caused by the shrubs Baccharis coridifolia and Baccharis artemisioides is very common in Argentina. The toxicity of Argentinian and Brazilian B. coridifolia plants and of Argentinian B. artemisioides was investigated. The toxicogenic capacity of 15 endothyte isolates of Ceratopicnidium baccharidicola from B. coridifolia was determined. Roridins and verrucarins were analyzed by thin-layer chromatography using a modified Jarvis method. One-hundred per cent of Argentinian B. coridifolia plants were positive for roridins (RA and RE) and verrucarins (VA and VJ), 16.2% for RD and 2.7% for RH. All of the Brazilian B. coridifolia plants were positive only for roridins. In B. artemisioides plants, RA, RE and RD were present in higher concentrations than VA and VJ, and all of them were more concentrated than in B. coridifolia. One-third of the endophyte isolates were toxicogenic for the same roridins and verrucarins, but in very low concentrations. This is the first report of macrocyclic trichothecenes in B. artemisioides, and a new report of B. coridifolia macrocyclic trichothecenes in Argentina.

Application of diluted chlorine dioxide to radish and lettuce nurseries insignificantly reduced plant development.

The possible toxicity of a commercial chlorine dioxide preparation (Halox E-100) was evaluated on radish and lettuce seedlings growing in pots under controlled conditions. A single application of various dilutions to radish seedlings growing in a sterile or nonsterile commercial plant substrate only slightly decreased plant dry weight. At the end of the experiments, the plants appeared unaffected by the treatments. Other common plant parameters (root and stem length, number of true leaves) were unaffected or even enhanced. Halox did not reduce the total level of soil bacteria even after four consecutive applications at any dilution rate. In nonsterile soil, high Halox dilution (1:1000) significantly decreased plant dry weight, and the other concentrations (1:10,000; 1:50,000, and 1:100,000) had no apparent effect on the size of the plants. In sterile soil, high concentrations of Halox (1:1000 and 1:10,000) significantly decreased plant growth, but higher dilutions produced no significant reduction in plant dry weight. For radish plants growing in organic matter-free sand only, dilution of 1:10,000 reduced plant growth. On lettuce plants, dilutions from 1:5000 to 1:25,000 did not reduce plant growth. High levels of Halox (1:1000) were toxic to both radish and lettuce seedlings growing in sand and resulted in chlorosis and significant depression of plant growth. Further dilutions of Halox (equivalent to the level used in water disinfection) significantly decreased toxicity for both plant species. Low concentrations of Halox (> 1:50,000) had no apparent effect on the appearance of both plant species. In conclusion, this study suggests that chlorine dioxide-treated drinking water can be considered safe for growing plants; this treatment should be further evaluated using other plant species under more realistic growth conditions.